Development of neutron reflector material brought about by nano-sized flowers; Structural control of nano-sized graphene and application for neutron reflector

Muramatsu, Kazuo*; Sutani, Koichi*; Kimishima, Koichi*; Teshigawara, Makoto   ; Ikeda, Yujiro*; Fukuzumi, Masafumi*; Koizumi, Satoshi*; Kawamura, Yuji*; Saruta, Koichi   ; Otake, Yoshie*

The use of nano-diamonds has been vigorously investigated to increase the intensity of neutron beams, focusing on the coherent scattering caused by nano-sized particle aggregations. Sp2 intercarbon-bonded graphene has a larger van der Waals force than sp3 intercarbon-bonded nano-diamonds. It is expected to be more easily formed into a lump shape and adaptability to higher radiation fields. On the other hand, the large cohesive nature of graphene makes it difficult to construct nano-sized three-dimensional structures. To solve this problem, we focused on the Hot Isostatic Pressing (HIP) method, which uses resin powder as a raw material and produces vapor-phase grown graphene. In this talk, we will report on the preparation of graphene flower structures, in which nano-sized graphene is three-dimensionally freestanding, how to control the nano-size of graphene, and a prototype of graphene neutron reflector material.